Low RCS Transmitarray Employing Phase Controllable Absorptive Frequency-Selective Transmission Elements

A low radar cross section (RCS) transmitarray is presented in this communication using phase controllable absorptive frequency-selective transmission (AFST) elements. The element consists of asymmetrical resonators with resistors to obtain an absorption-transmission-absorption response. The transmission phase within the transmission band can be controlled by rotating the AFST elements, achieving a 1 bit phase change. A low-RCS transmitarray using the developed elements is designed, fabricated, and measured. Compared with a reference transmitarray, the radiation performance of the low-RCS one is almost unchanged with a realized gain of 24.4 dBi. Significant RCS reductions have been realized for dual polarizations of the impinging electromagnetic (EM) waves. The 10 dB RCS reduction bandwidths are 18% and 14% for the lower and upper absorption bands, respectively.